One common scenario when working with Git is accidentally deleting files or making changes to a file that you later realize were not necessary. In such cases, Git provides some very useful commands to recover your data.
1. git checkout
If you have modified a file and haven’t committed your changes, you can revert those changes using the git checkout command. This switches your head back to the specified previous state, effectively undoing your changes.
Example:
git checkout filename
2. git revert
The git revert command can undo the changes of a specific commit. This is done by creating a new commit that inverses the changes made in the original commit. This is a safe way to undo changes, as it does not erase the commit history.
Example:
git revert commit_id
3. git reset
Git reset is a more powerful, but potentially dangerous command as it allows you to change your commit history. Git reset has three main modes: soft, mixed, and hard.
- `git reset –soft`: Moves your head to the specified commit, but leaves your files & staging area unchanged.
- `git reset –mixed`: Moves your head to the specified commit and changes the staging area to match this commit, but leaves your files unchanged. This is the default mode.
- `git reset –hard`: Moves your head to the specified commit, and changes both your staging area and your files to match this commit.
Example:
git reset --soft commit_id
git reset --mixed commit_id
git reset --hard commit_id
4. git reflog & git checkout
Sometimes you may lose a commit entirely, such as after performing a hard reset. In these situations, git reflog can be your saving grace. Git reflog logs all the actions that move HEAD, allowing you to find lost commits. You can then use git checkout to recover your data from these commits.
Example:
View the reflog:
git reflog
Recover lost commit:
git checkout commit_id
By using these Git commands adeptly, you can demystify data loss and ensure you always have the ability to return to a safe state, be it during development, testing, or even production stages.
Moreover, from the lens of the AZ-400 exam, understanding these commands deepens your comprehension of Git as a version control system and enhances your ability to design and implement robust DevOps solutions.
Remember, practice makes perfect. So, don’t hesitate to explore and experiment (in safe environments, of course). Soon, you’ll find recovering data using Git to be a breeze.
Practice Test
True or False: ‘git checkout’ is a powerful command that you can use to switch between branches in a Git repository.
- Answer: True
Explanation: ‘git checkout’ is indeed a commonly used command for switching between branches in a Git repository.
Which Git command would you use to see the commit history?
- A. git log
- B. git history
- C. git view
- D. git inspect
Answer: A. git log
Explanation: The ‘git log’ command is used for viewing the history of commits.
You can recover deleted files in Git using the ‘git restore’ command. (True/False)
- Answer: True
Explanation: ‘git restore’ command can be used to unstage or even discard uncommitted local changes.
In Git, if you accidentally deleted a branch, you can still recover it. (True/False)
- Answer: True
Explanation: Git keeps a log of everything for some days. You can use the ‘git reflog’ command to find the pointer to the old commit on that branch and recover it.
Which of the following command will allow you to amend the most recent commit message in Git?
- A. git commit –amend
- B. git amend
- C. git edit
- D. git message -u
Answer: A. git commit –amend
Explanation: The ‘git commit –amend’ command is used to make changes to the most recent commit.
The Git command to recover a specific file that you lost is:
- A. git get
- B. git retrieve
- C. git restore
- D. git recover
Answer: C. git restore
Explanation: ‘git restore’ command allows you to recover a specific lost file.
Is it possible to recover changes to your working directory which have never been staged or committed?
- A. Yes
- B. No
Answer: B. No
Explanation: Git tracks only content that has been staged or committed. Changes to working directory that have never been staged or committed can’t be recovered.
The git command to revert changes made to your working copy to the most recent commit is:
- A. git revert
- B. git undo
- C. git reset –hard
- D. git restore
Answer: C. git reset –hard
Explanation: ‘git reset –hard’ removes all changes since the last commit, cleaning your working copy.
The ‘git stash’ command can be used to save changes that are not ready to be committed. (True/False)
- Answer: True
Explanation: ‘git stash’ temporarily shelves changes you’ve made to your working copy so you can work on something else, and then come back and re-apply them.
What is the command to view changes in the Git staging area?
- A. git diff
- B. git view-stage
- C. git log
- D. git changes
Answer: A. git diff
Explanation: ‘git diff’ command lets you compare changes in your working directory with changes in the staging area.
True or False: ‘git cherry-pick’ is a powerful command that you can use to apply the changes introduced by some existing commits.
- Answer: True
Explanation: ‘git cherry-pick’ command applies the changes of a committed snapshot from one line of development onto another in the exact way they occurred, enabling the recovery of selective changes.
Which Git command would create a new branch?
- A. git branch
- B. git checkout
- C. git create
- D. git new
Answer: A. git branch
Explanation: The ‘git branch’ command lets you create, list, rename, and delete branches.
You can use the ‘git revert’ command to undo a public commit. (True/False)
- Answer: True
Explanation: The ‘git revert’ command generates a new commit that undoes all changes that were made in the bad commit, it’s safe to use on public commits.
True or False: Git repositories can be cloned using the ‘git clone’ command.
- Answer: True
Explanation: The ‘git clone’ command creates a copy of an existing Git repository.
You can use the ‘git fetch’ command to download objects and refs from another repository. (True/False)
- Answer: True
Explanation: ‘git fetch’ command gets the latest changes from an upstream repository without merging them in.
Interview Questions
Name the Git command that will show you the difference between the current state of your working directory and the last commit?
The command is “git diff”.
What is the Git command to recover a deleted file?
The command is “git checkout <file_name>”.
How can you use Git to revert a commit?
The command is “git revert <commit_id>”.
What is the purpose of the git fsck command in Git?
The ‘git fsck’ command is used for verifying the connectivity and validity of the objects in the database.
Which command is used to undo most recent commit in Git?
The command to undo most recent commit in Git is ‘git reset –soft HEAD~1’.
How would you go back to a particular commit in Git?
You can go back to a particular commit in Git using the ‘git checkout <commit_id>’ command.
How do we revert changes in the working directory using Git?
We can revert changes in working directory using ‘git checkout — <filename>’.
What git command is used to discard any uncommitted local changes?
The command ‘git stash’ is used to discard any uncommitted local changes.
What is the use of ‘git reflog’ command?
The ‘git reflog’ command is used to reference logs and keep track of when the tips of branches and other references were updated in the local repository.
How can you move HEAD back to a previous location with Git?
You can move HEAD back to a previous location using the ‘git reset –hard HEAD~1’ command.
What command is used to remove untracked files from the current working directory in Git?
The command ‘git clean -f’ is used to remove untracked files from the current working directory.
How can you recover a dropped stash in Git?
You can recover a dropped stash in Git using the ‘git stash apply’ command with the appropriate stash id.
What is the use of ‘git checkout — .’ in Git?
The ‘git checkout — .’ command is used to discard all the changes in the directory and revert to the last commit.
How would you recover a branch if it was inadvertently deleted in Git?
If inadvertently deleted, a branch can be recovered in Git using ‘git branch <branch_name> <SHA1_OF_PREVIOUS_HEAD>’.
What Git command to use to download objects and refs from another repository?
The command to download objects and refs from another repository in Git is ‘git fetch’.
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